I believe this is not a fair assessment as a lot has to do with the crypto project itself.
Its a matter of perspective really, not all bounty hunters have the same experience or motive, some people just need an opportunity to get crypto for projects that are very difficult to get in the token sales, Example is Ncash tokens of Nucleus.Vision the project has a 1 million USD budget and it is still above ICO price even in the bear market.
Additionally some projects treat bought hunters badly which will not encourage them to stick around for much longer after they get their tokens.
I believe tokens or coins getting dumped by bounty hunters depends a lot on the project itself.
if the project is good and the "hunter" considers it promising - then the coins will hold
There will or will not be additional bonuses - not so important as the perspective of the token rate